German Published Patent Application No. 35 03 451 refers to a device having a sensor device which encompasses several sensors with which light conditions in the vicinity of the vehicle are sensed. The sensor device is connected to an evaluation device in which, from the signals of the sensor device, a determination is made as to whether a change in the switching state of the illumination devices is necessary given the current light conditions in the vicinity of the vehicle. This device may provide automatic switching of the illumination devices, i.e. headlights and tail lights, of the vehicle as general light conditions change, but certain changes in the light conditions in the vicinity of the vehicle cannot or may not be detected by the device.
In difficult light conditions in particular, for example at twilight, the illumination devices may be unfavorably switched off.